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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #394570

Research Project: Computational Tools and a Decision Support System for Management of Sediment and Water Quality in Agricultural Watersheds

Location: Watershed Physical Processes Research

Title: Numerical simulation of dynamic processes of flow and salinity in Lake Pontchartrain and Mississippi Sound due to Bonnet Carre Spillway flood release

item CHAO, XIAOBO - University Of Mississippi
item ZHANG, YAOXIN - University Of Mississippi
item AL-HAMDAN, MOHAMMAD - University Of Mississippi

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2021
Publication Date: 12/13/2021
Citation: Chao, X., Zhang, Y., Al-Hamdan, M. 2021. Numerical simulation of dynamic processes of flow and salinity in Lake Pontchartrain and Mississippi Sound due to Bonnet Carre Spillway flood release. American Geophysical Union. 2021.

Interpretive Summary:

Technical Abstract: In response to the Great Mississippi Flood of 1927 and to protect the city of New Orleans, the Bonnet Carré Spillway (BCS) was constructed from 1929 to 1936 to divert the excessive flood water from Mississippi River into the Gulf of Mexico through Lake Pontchartrain. It was first opened for flood release in 1937, and 14 times thereafter through 2020. During the BCS flood releases, large amounts of freshwater, sediment, nutrients and other pollutants were discharged into lake Pontchartrain and the Gulf of Mexico, and significantly affected water quality and aquatic environment in these water-bodies. It was observed the salinity in Mississippi Sound dropped to a very low level and greatly affect the growth of oyster and other aquatic organisms. A numerical model (CCHE2D) developed at the National Center for Computational Hydro-science and Engineering (NCCHE), the University of Mississippi, was applied to simulate the dynamic process of hydrodynamics and salinity distributions in Northern Gulf of Mexico due to BCS opening for flood release in 2019. The computational domain includes Atchafalaya River, Mississippi River, Lake Pontchartrain, Pearl River, Mississippi Sound and Mobile Bay (Figure 1). The flow fields in this area are mainly induced by river flow, tide flow and wind force. The simulation results are calibrated and validated using field observed data obtained from NOAA and US Army Corp of Engineers. The effects of BCS flood release and Pearl River flow discharge on the salinity decrease in Lake Pontchartrain and Mississippi Sound are analyzed. This model is also applied to simulate the salinity recovery processes in Lake Pontchartrain and Mississippi Sound. This research provides useful information for understanding the effects of BCS flood release on the aquatic organisms in the marine environments.